A beloved teacher, doctor and AIDS researcher was found dead in the Hudson River.

Dr. Charles Michael van der Horst died on June 14, at the end of a marathon swim in the Hudson River of an apparent cardiac event, according to his obituary.

The 67-year-old from North Carolina was participating in the 8 Bridges Hudson River Swim. van der Horst went missing after he went under the near water near the George Washington Bridge, during the second-to-last stage of the multi-day race,

The 120-mile race starts at the Rip Van Winkle Bridge between Hudson and Catskill. van der Horst's last completed part of the race was from the Newburgh-Beacon Bridge to Bear Mountain Bridge, the New York Daily News reports.

The part of the race where he went missing starts at the Tappan Zee Bridge and ends at the George Washington Bridge. The end of the race was canceled as rescuers searched the water for the 67-year-old, but he was confirmed dead shortly after.

Last year, van der Horst wrote about participating in the race in the News Observer.

"Racing 15 miles in the Hudson River beneath the cliffs of West Point, dwarfed by an oil tanker with its propellers moving whump, whump, whump like some whale in heat, brought perspective as to the vastness of nature," he wrote.

van der Horst was a Professor of Medicine at the University of North Carolina, Chapel Hill. He also worked passionately on the front lines of the HIV epidemic, both in the United States and Africa, according to his obituary.

"I’m heartbroken and deeply saddened to learn the passing of my good friend, a friend to the community and an amazing kind hearted social justice warrior, Dr. Charles Van Der Horst. He was an advocate for Medicare for All and huge part of Moral Monday Movement. What an amazing wonderful human being Charles was and the impact he made in the field of AIDS research, medicine and the community," Faisal R. Khan wrote on Facebook.

The 67-year-old is originally from Olean, New York, according to his obituary.

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